1. Field of the Invention
The invention relates to apparatus for the spatial location and destruction of an object inside a patient's body by means of ultrasound which is transmitted to the patient's body via a coupling fluid, which is used for the destruction of the object, and which is generated piezoelectrically by means of a focusing transducer and wherein the focus of the transducer is aligned with the object under observation following location of the object by means of transmitting and receiving locating transducers.
2. Description of the Prior Art
The location of objects within a patient's body which are to be destroyed, such as stone concretions, tissue sections and the like, may be carried out under observation using X-ray or ultrasound technology. However, X-ray technology has particular disadvantages including exposure of the patient to radiation and unsuitability for performing simultaneous observation of the process of destruction of the object. The two locating techniques may obviously also be combined, for example by performing the continuous location and observation by means of ultrasound, and by checking the therapeutic results from time to time by means of X-rays. However, the provision of locating systems to perform this method would involve comparatively large expenditures. Accordingly, systems which use ultrasound only for locating the object and for checking on the therapeutic result obtained are more satisfactory. If the therapeutic ultrasound is generated by means of a cup or bowl shaped focusing transducer comprising a piezoelectric element or a mosaic of several piezoceramic elements, an ultrasonic B-scanner may be provided. Such a B-scanner can be arranged to scan a sector shaped field for example, at the center, coincident with the axis of the transducer cup or bowl, to produce a B-image. The focus of the focusing transducer is provided as a target mark on a monitor, so that it is possible to establish from the position of the object depicted by the B-image with respect to the target mark by what distance the focusing transducer should be displaced with respect to the patient in one plane or several planes so that the focus may finally be aligned precisely with the object. The locating action and alignment of the transducer may then also be performed in another plane, by turning the B-scanner through 90.degree. for example. On the other hand, it is equally possible to operate with several locating transducers each of which transmits ultrasound waves. In such a case, the locating transducers also may simultaneously be positioned and arranged to receive the echo signals from these waves, unless it is preferred to receive the echo signals by means of separate ultrasound or pressure receivers.
However, problems arise with such location systems since, in certain disadvantageous positions of the locating, the effective transducer area can be masked by the locating transducers, causing a loss of active focusing transducer area. Furthermore, until now physicians did not have the means of establishing without difficulty the precise dimensions of an object. This is of importance to enable the physician even at the beginning of the treatment if possible, to determine the precise point at which the object (such as a kidney stone for example) should first and preferentially be bombarded with ultrasound to secure optimum results.
Accordingly, the main object of the present invention is to provide a structurally uncomplicated and highly efficient apparatus for spatial location and destruction of objects inside the body, which provides the physician with improved capabilities for locating and continuously monitoring the position as well as destruction of the object.